Fecal microbiotal transplantation as a method for improving the outcomes of the dual radio- and immunotherapies within a colorectal cancer mouse model.

Colorectal cancer (CRC) is the third commonly diagnosed cancer and fourth cause of cancer death worldwide. An altered microbiome, also known as dysbiosis, can often be seen in CRC patients. Radiotherapy and immunotherapy are known treatment options for colorectal cancer, but are associated with toxicity and heterogeneous responses, respectively. Fecal microbiotal transplantation (FMT) has been shown to reduce radiation-induced toxicity and dysbiosis in mice and improve immunotherapy responsiveness in patients. To date, FMT has never been introduced with the dual therapy of radiotherapy and immunotherapy. Therefore, it is not clear whether this combined treatment will result in improved treatment outcome, lesser side-effects, tumor burden etc. In this project, we first intend to characterize the effects of dual radiotherapy and immunotherapy using the well-established azoxymethane (AOM)/dextran sodium sulfate (DSS) CRC mouse model. CRC mice will be treated with radiotherapy, immunotherapy or dual radiotherapy and immunotherapy, after which diagnostic microbial biomarkers for immunotherapy responsiveness and predictive microbial biomarkers of treatment outcome will be determined. Additionally, we plan to study if and how FMT can tackle radiation-induced dysbiosis and immunotherapy efficiency. Throughout the experiment, fecal samples will be collected and used to perform 16S microbial profiling. Tumor load (number, size, area), histo-pathological analysis (e.g. stem cell proliferation, apoptosis, mucus formation), inflammatory/immunological markers and proteomics analysis will be performed and correlated with the microbial dynamics to identify predictive and diagnostic biomarkers for treatment outcome and side-effects. Additionally, flow cytometry analysis, stainings and protein quantification assays for tight junctions will be used to assess bacterial translocation. FMT will be introduced in an anaerobic bag and similar experiments as explained above will be performed to determine if FMT can improve treatment outcome and side-effects. Meta-proteomics and meta-transcriptomics will be performed and will be integrated in an integrative omics analysis with the metagenomics to help understand the functional involvement of FMT in improving treatment outcome and side-effects.

Keywords:COLORECTAL CANCER

Disciplines:Cancer biology

Project type:Collaboration project